The present invention generally relates to a system and a method for stabilizing a diode laser frequency to an atomic transition. More specifically, the present invention relates to a method that employs Zeeman shift to stabilize a diode laser frequency.
Lasers with stable frequencies are essential in many fields of research. In addition, such lasers are used commercially in precision machining tools, gravimeters, and laser vibrometers. He-Ne lasers have been an industry standard for many years (see U.S. Pat. No. 3,534,292 to Cutler), but they are generally bulky, energy inefficient and have limited tube lifetimes.
Diode lasers offer an improvement in all these areas and may be stabilized to atomic transitions. Typical methods of stabilization as described in, for example, C. E. Wieman et al., "Using Diode Lasers for Atomic Physics," Rev. Sci. Instrum., 62, 1191, pp. 1-20 and K. B. MacAdam et al., "A Narrow-Band Tunable Diode Laser System with Grating Feedback and a Saturated Absorption Spectrometer for Cs and Rb," Am. J. Phys, 60, 1992, pp. 1098-1111. While these stabilization methods may be practical in some laboratory settings, they are not reliable enough for use in commercial equipment.
The present invention, however, overcomes the deficiencies of previous methods. Using a technique originally demonstrated with an LNA laser in helium (see B. Cheron et al., "Laser Frequency Stabilization Using Zeeman Effect," J. Phys. III, 4, 1994, pp. 401-406), the present invention sets forth a very robust diode laser stabilization scheme that may be useful in both commercial instruments and research laboratories.